Among the indirect printing processes currently in use, the ones that use inks, for example of the sublimating type, consist in transferring an image previously deposited on a plate-like medium, commonly known as transfer medium, onto the surface of an object to be decorated, which is known as imprintable item.
One of the fundamental requirements for achieving a satisfactory resolution of the printed image is that during the transfer the transfer medium must: be perfectly in contact with the imprintable medium, so that the inks, by sublimating, penetrate the imprintable surface uniformly and homogeneously.
From the above description it is evident that in order to perform the sublimation transfer of an image onto a contoured surface it is necessary to adopt a transfer medium that is capable of adhering exactly to the surface of the imprintable item, and in this case media made of paper-like material or the like are inadequate, producing considerable printing defects caused by the inevitable creases.
This has led to interest in using, for the transfer of images onto irregular surfaces, transfer mediums made of elastic materials, such as for example elasticized cotton fabrics, which however have considerable drawbacks due both to the particularly high costs of the fabrics used and to the fact that their woven structure often compromises printing quality, considerably reducing the degree of fidelity of the reproduced image.
If a medium made of elastoplastic material is used, one observes during the transfer of the ink in the vaporization phase an enormous difficulty in draining the gas, with consequent forming of bubbles and reduction of the quality of the final surface.